1. Field of the Invention
The invention relates in general to semiconductor packaging technology using a leadless leadframe, and more particularly to a leadless semiconductor package and the manufacturing method for the same.
2. Description of the Related Art
Conventional semiconductor package uses a chip carrier to carry and electrically connects a semiconductor chip, such as a circuit substrate and a leadframe. Using the leadless leadframe as the chip carrier has the advantages of low cost and small scale. After packaging, the arrangement and number of the leadframe inner leads are subject to the restriction of the manufacturing process and design of the leadless leadframe, thus having limited application.
Referring to FIGS. 1 and 2, a conventional leadless semiconductor package 1 includes a chip pad 11, a plurality of inner leads 12, a semiconductor chip 20 and a molding compound 30. The chip pad 11 and the inner leads 12 are components of a leadless leadframe. As shown in FIG. 2, the inner leads 12 are formed on the outer periphery of the chip pad 11. The chip pad 11 is coupled to the leadframe via a plurality of tie bars 13. As shown in FIG. 1, a rear surface 22 of the semiconductor chip 20 is disposed on the chip pad 11 via an adhesive 24. One active surface 21 of the chip 20 has a plurality of bonding pads 23. The bonding pads 23 of the chip 20 are coupled to the inner leads 12 via a plurality of bonding wires 25. The molding compound 30 is used to encapsulate the chip 20 and the bonding wires 25. Conventional molding compound 30 is made through molding. To prevent the inner leads 12 and the bottom surface of the chip pad 11 from being contaminated by the residual of the molding compound 30 due to the compression and diffusion of the compound, a conventional practice is to attach an external tape 40 to completely cover up the inner leads 12 and the bottom surface of the chip pad 11 (shown in FIG. 1). Accordingly, the molding compound 30 does not contaminate the inner leads 12 and the bottom surface of the chip pad 11, and the external tape 40 is removed after the molding compound 30 is formed. So, the external tape 40 is a consumable material during manufacturing process that can not exist inside the leadless semiconductor package 1. However, extra steps are required in the manufacturing process to attach and remove the external tape 40. Moreover, the chip pad 11 has to be connected via a plurality of tie bars 13. Normally, the tie bars 13 should correspond to the four corners of the molding compound 30, and the inner leads 12 should have considerable width to provide enough structural strength to be connected to the frame bars of the leadframe. Therefore, the arrangement of the chip pad 11 and the inner leads 12 are subject to the manufacturing process of the leadframe and can not be in an optional location.